Ultrasonographic measurement of normal common bile duct diameter and its correlation with age, sex and anthropometry

The Diameter of the Normal Extrahepatic Bile Duct among Patients Diagnosed with Cholecystolithiasis Managed at the Philippine General Hospital

Background and Objective

Understanding the normal anatomy and size of the extrahepatic biliary tree is vital for surgeons to make informed decisions regarding the necessity of additional procedures beyond cholecystectomy. The extrahepatic bile duct (EHBD) comprises the common hepatic duct (CHD) and the common bile duct (CBD), with the former formed by the convergence of the right and left hepatic ducts and the latter extending from the CHD to the duodenum. A normal diameter is indicative of the absence of any signs of obstruction in the EHBD, and the determination of the average range for these ducts are essential for identifying pathologies that may require further surgical intervention. Cholecystolithiasis is a common condition managed at the Philippine General Hospital (PGH). Trans-abdominal ultrasonography is frequently utilized to diagnose cholecystolithiasis, and it can also be used to determine the size of the common bile duct. Knowledge of the normal CBD diameter aids clinicians in distinguishing obstructed bile ducts from normal ones, prompting further diagnostic tests for improved patient management. However, there is limited data on the average diameter of the CBD among Filipino patients with this condition. The study aimed to determine the mean diameter of the common bile duct and common hepatic duct among patients diagnosed with cholecystolithiasis with no signs of obstruction in the EHBD managed at the PGH.

Methods

This prospective cross-sectional study included 80 patients who underwent cholecystectomy with intraoperative cholangiography. The CBD and CHD diameters were measured using intraoperative ultrasonography, and the data were analyzed using descriptive statistics and independent t-test.

Results

The mean diameter of the CBD was 5.17 mm, with a range of 2.7-10 mm (1.41) mm. The mean diameter of the CHD was 4.71 mm, with a range of 2.3- 10 mm (1.59) mm. There was no significant difference in the CBD and CHD diameters between male and female patients, and across different age groups.

Conclusion

In patients with cholecystolithiasis managed at the PGH, the mean diameter of the CBD and the CHD was 5.17 mm and 4.71 mm, respectively, with no significant difference between genders and age groups. The mean diameter of the CBD among Filipino patients with cholecystolithiasis is similar to those reported in other countries. These findings may have clinical implications for the management of patients with cholecystolithiasis, particularly in the planning of endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy. Further studies with larger sample sizes and different populations are recommended to validate these results. These findings can aid clinicians in determining the need for pre-operative Magnetic Resonance Cholangiopancreatography (MRCP) or selective intraoperative cholangiography to detect extrahepatic bile duct obstruction.

Utility of Common Bile Duct Identification on Biliary Ultrasound in Emergency Department Patients

Background

Biliary ultrasound is often utilized in the evaluation of abdominal pain in the Emergency Department (ED). Common bile duct (CBD) identification is traditionally a standard component of the biliary ultrasound examination but can be challenging to perform for the novice sonographer. Previous work has demonstrated that CBD dilatation is rare in cases of cholecystitis with normal liver function tests (LFTs). We sought to assess the frequency of CBD dilatation in the subset of ED patients undergoing hepatobiliary ultrasound who have normal LFTs and an absence of gallstones or biliary sludge on ultrasound. We also performed an assessment of changes in CBD diameter by age and cholecystectomy status.

Methods

This was a retrospective chart review at a single academic ED. Patients were enrolled in the study if they underwent a radiology performed (RP) hepatobiliary ultrasound within the 2 year study period. Records were reviewed for the presence of gallstones or sludge, CBD diameter, age, clinical indication for the ultrasound, and LFTs. Descriptive analyses were performed, and interobserver agreement among data abstractors was assessed by K analysis for the presence of CBD dilatation. The Mann-Whitney test was utilized to assess statistical significance in the comparison of differences between CBD diameters amongst age groups.

Results

Of 1929 RP hepatobiliary ultrasounds performed in the study period, 312 were excluded and 1617 met inclusion criteria. Amongst these, there were 506 patients who had normal LFTs and an ultrasound with no stones or sludge. Ten patients within this group had a dilated CBD > 7 mm (1.98%, 95% CI of 1.08% to 3.6%). We also noted a statistically significant increase in CBD size in the older age cohort and in those individuals with a history of cholecystectomy.

Conclusion

CBD dilation in ED patients who present with normal LFTs and an absence of gallstones and biliary sludge is rare. Physicians should be reassured that the routine identification of the CBD on ultrasound in this setting is of low yield and need not be pursued.

Therapeutic biliary stents: applications and opportunities

INTRODUCTION

Biliary stents are used to optimize ductal patency and enable bile flow in the management of obstruction or injury related to biliary tract tumors, strictures, stones, or leaks. Although direct therapeutic applications of biliary stents are less well developed, stents can be used to deliver drugs, radioisotopes, and photodynamic therapy.

AREAS COVERED

This report provides an in-depth overview of the clinical indications, and therapeutic utility of biliary stents. Unique considerations for the design of biliary stents are described. The properties and functionalities of materials used for stents such as metal alloys, plastic polymers, or biodegradable materials are described, and opportunities for design of future stents are outlined. Current and potential applications of stents for therapeutic applications for biliary tract diseases are described.

EXPERT OPINION

Therapeutic biliary stents could be used to minimize inflammation, prevent stricture formation, reduce infections, or provide localized anti-cancer therapy for biliary tract cancers. Stents could be transformed into therapeutic platforms using advanced materials, 3D printing, nanotechnology, and artificial intelligence. Whilst clinical study and validation will be required for adoption, future advances in stent design and materials are expected to expand the use of therapeutic biliary stents for the treatment of biliary tract disorders.

Augmented Reality Navigation System for Biliary Interventional Procedures With Dynamic Respiratory Motion Correction

OBJECTIVE

Biliary interventional procedures require physicians to track the interventional instrument tip (Tip) precisely with X-ray image. However, Tip positioning relies heavily on the physicians' experience due to the limitations of X-ray imaging and the respiratory interference, which leads to biliary damage, prolonged operation time, and increased X-ray radiation.

METHODS

We construct an augmented reality (AR) navigation system for biliary interventional procedures. It includes system calibration, respiratory motion correction and fusion navigation. Firstly, the magnetic and 3D computed tomography (CT) coordinates are aligned through system calibration. Secondly, a respiratory motion correction method based on manifold regularization is proposed to correct the misalignment of the two coordinates caused by respiratory motion. Thirdly, the virtual biliary, liver and Tip from CT are overlapped to the corresponding position of the patient for dynamic virtual-real fusion.

RESULTS

Our system is respectively evaluated and achieved an average alignment error of 0.75 ± 0.17 mm and 2.79 ± 0.46 mm on phantoms and patients. The navigation experiments conducted on phantoms achieve an average Tip positioning error of 0.98 ± 0.15 mm and an average fusion error of 1.67 ± 0.34 mm after correction.

CONCLUSION

Our system can automatically register the Tip to the corresponding location in CT, and dynamically overlap the 3D virtual model onto patients to provide accurate and intuitive AR navigation.

SIGNIFICANCE

This study demonstrates the clinical potential of our system by assisting physicians during biliary interventional procedures. Our system enables dynamic visualization of virtual model on patients, reducing the reliance on contrast agents and X-ray usage.

Analysis and numerical investigation of bile flow dynamics within the strictured biliary duct

The mechanics of bile flow in the biliary system plays an important role in studying bile stasis and gallstone formation. Bile duct stricture is an abnormal phenomenon that refers to the bile duct getting smaller or narrower. The main objective of this study is to study the influence of stricture on bile flow dynamics using numerical methods. We employed a numerical Computational Fluid Dynamics model of the bile flow within a strictured hepatic duct. We studied and compared the influence of stricture severity, stricture length, eccentricity, and bile flow property on the bile flow dynamics. The bile flow velocity, pressure distribution, pressure drop, and wall shear stress are provided in detail. The stricture alters the normal bile flow pattern and increases flow resistance. At the location upstream and downstream of the stricture, bile flow slows down. In the area of the stricture throat, bile flow is accelerated, and recirculation forms behind the stricture. The maximum pressure drop of the biliary system increases with the stricture length. The eccentricity makes the flow deflect away from the duct's centerline. The behavior of the deflected flow is significantly altered downstream of the stricture. Such bile flow behavior as deceleration and recirculation may lead to cholestasis. Stricture alters bile flow in the biliary tract, causing changes in biliary hydrodynamic indexes, which could potentially serve as an omen for gallstone formation and other related diseases. The consideration of the bile duct stricture could lead to better patient stratification.

Computed tomographic quantitative evaluation of common bile duct size in normal dogs: A reference range study considering body weight

Introduction

Common bile duct (CBD) measurements are important for the evaluation of biliary systemic disorders. However, in veterinary medicine, reference ranges for specific body weights (BW) and correlation between CBD diameter and BW have not been studied. This study aimed to establish normal reference ranges of CBD diameter for different BW groups and to analyse correlation between CBD diameter and BW in dogs without hepatobiliary disease. Additionally, normal reference ranges of CBD to aorta ratio (CBD: Ao ratio) were established which is not affected by BW.

Methods

CBD diameter was measured at three different sites: porta hepatis (PH), duodenal papilla (DP) level and mid-portion (Mid) between these points using computed tomography (CT) in 283 dogs without hepatobiliary disease.

Results

The reference range of CBD diameter at PH level: 1.69 ± 0.29 mm (Class 1; 1 kg ≤ BW < 5 kg), 1.92 ± 0.35 mm (Class 2; 5 kg ≤ BW < 10 kg), 2.20 ± 0.43 mm (Class 3; 10 kg ≤ BW < 15 kg), 2.79 ± 0.49 mm (Class 4; 15 kg ≤ BW < 30 kg); Mid-level: 2.06 ± 0.25 mm (Class 1), 2.43 ± 0.37 mm (Class 2), 2.74 ± 0.52 mm (Class 3), 3.14 ± 0.44 mm (Class 4); DP level: 2.33 ± 0.34 mm (Class 1), 2.90 ± 0.36 mm (Class 2), 3.35 ± 0.49 mm (Class 3), and 3.83 ± 0.50 mm (Class 4). There was a significant difference in CBD diameter at each level among all BW groups. Furthermore, BW and CBD diameter showed positive linear correlation at each level. We devised CBD: Ao ratio at each level that showed no significant difference between the different BW groups; PH level: 0.34 ± 0.05; Mid-level: 0.42 ± 0.06; DP level: 0.47 ± 0.06.

Conclusion

In conclusion, since the CBD diameter for each BW is significantly different, different normal reference ranges of CBD diameter should be applied for each BW, and the CBD: Ao ratio can be used regardless of the BW.

Utilizing CT to identify clinically significant biliary dilatation in symptomatic post-cholecystectomy patients: when should we be worried?

PURPOSE

To determine a reliable threshold common duct diameter on CT, in combination with other ancillary CT and clinical parameters, at which the likelihood of pathology requiring further imaging or intervention is increased in post-cholecystectomy patients.

METHODS

In this IRB approved retrospective study, two attending radiologists independently reviewed CT imaging for 118 post-cholecystectomy patients, who were subsequently evaluated with MRCP, ERCP, or EUS, prompted by findings on the CT and clinical status. Measurements of the common duct (CD) were obtained at the porta hepatis, distal duct, and point of maximal dilation on axial and coronal CT scans. Patients were grouped by whether they required intervention after follow-up imaging. Pertinent baseline lab values and patient demographics were reviewed.

RESULTS

Of the 118 post-cholecystectomy patients, 38 patients (31%) required intervention, and 80 patients (69%) did not require intervention after follow-up imaging. For both readers, axial and coronal CD diameters were significantly higher in the 'intervention required' vs 'no intervention' groups at all locations (p value < 0.05). There was good to excellent inter-reader agreement at all locations (ICC 0.68-0.92). Pertinent baseline lab values including AST (p = 0.043), ALT (p = 0.001), alkaline phosphatase (p = 0.0001), direct bilirubin (p = 0.011), total bilirubin (p = 0.028), and WBC (p = 0.043) were significantly higher in the 'intervention required' group. CD thresholds of 8 mm yielded the highest sensitivities (76-95%), and CD thresholds of 12 mm yielded the highest specificities (65-78%). CD combined with bilirubin levels increased sensitivity and specificity, compared to using either feature alone.

CONCLUSION

Dilated CD on CT combined with bilirubin levels increases the sensitivity and specificity for identifying patients needing intervention. We recommend that a post-cholecystectomy patient who presents with a CD diameter > 10 mm on CT and elevated bilirubin levels should undergo further clinical and imaging follow-up.

Rapid diagnosis and tumor margin assessment during pancreatic cancer surgery with the MasSpec Pen technology

Intraoperative delineation of tumor margins is critical for effective pancreatic cancer surgery. Yet, intraoperative frozen section analysis of tumor margins is a time-consuming and often challenging procedure that can yield confounding results due to histologic heterogeneity and tissue-processing artifacts. We have previously described the development of the MasSpec Pen technology as a handheld mass spectrometry-based device for nondestructive tissue analysis. Here, we evaluated the usefulness of the MasSpec Pen for intraoperative diagnosis of pancreatic ductal adenocarcinoma based on alterations in the metabolite and lipid profiles in in vivo and ex vivo tissues. We used the MasSpec Pen to analyze 157 banked human tissues, including pancreatic ductal adenocarcinoma, pancreatic, and bile duct tissues. Classification models generated from the molecular data yielded an overall agreement with pathology of 91.5%, sensitivity of 95.5%, and specificity of 89.7% for discriminating normal pancreas from cancer. We built a second classifier to distinguish bile duct from pancreatic cancer, achieving an overall accuracy of 95%, sensitivity of 92%, and specificity of 100%. We then translated the MasSpec Pen to the operative room and predicted on in vivo and ex vivo data acquired during 18 pancreatic surgeries, achieving 93.8% overall agreement with final postoperative pathology reports. Notably, when integrating banked tissue data with intraoperative data, an improved agreement of 100% was achieved. The result obtained demonstrate that the MasSpec Pen provides high predictive performance for tissue diagnosis and compatibility for intraoperative use, suggesting that the technology may be useful to guide surgical decision-making during pancreatic cancer surgeries.

Reconfigurable multifunctional ferrofluid droplet robots

Magnetically actuated miniature soft robots are capable of programmable deformations for multimodal locomotion and manipulation functions, potentially enabling direct access to currently unreachable or difficult-to-access regions inside the human body for minimally invasive medical operations. However, magnetic miniature soft robots are so far mostly based on elastomers, where their limited deformability prevents them from navigating inside clustered and very constrained environments, such as squeezing through narrow crevices much smaller than the robot size. Moreover, their functionalities are currently restricted by their predesigned shapes, which is challenging to be reconfigured in situ in enclosed spaces. Here, we report a method to actuate and control ferrofluid droplets as shape-programmable magnetic miniature soft robots, which can navigate in two dimensions through narrow channels much smaller than their sizes thanks to their liquid properties. By controlling the external magnetic fields spatiotemporally, these droplet robots can also be reconfigured to exhibit multiple functionalities, including on-demand splitting and merging for delivering liquid cargos and morphing into different shapes for efficient and versatile manipulation of delicate objects. In addition, a single-droplet robot can be controlled to split into multiple subdroplets and complete cooperative tasks, such as working as a programmable fluidic-mixing device for addressable and sequential mixing of different liquids. Due to their extreme deformability, in situ reconfigurability and cooperative behavior, the proposed ferrofluid droplet robots could open up a wide range of unprecedented functionalities for lab/organ-on-a-chip, fluidics, bioengineering, and medical device applications.

Quantitative MRCP Imaging: Accuracy, Repeatability, Reproducibility, and Cohort-Derived Normative Ranges

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) is an important tool for noninvasive imaging of biliary disease, however, its assessment is currently subjective, resulting in the need for objective biomarkers.

PURPOSE

To investigate the accuracy, scan/rescan repeatability, and cross-scanner reproducibility of a novel quantitative MRCP tool on phantoms and in vivo. Additionally, to report normative ranges derived from the healthy cohort for duct measurements and tree-level summary metrics.

STUDY TYPE

Prospective.

PHANTOMS/SUBJECTS

Phantoms: two bespoke designs, one with varying tube-width, curvature, and orientation, and one exhibiting a complex structure based on a real biliary tree. Subjects Twenty healthy volunteers, 10 patients with biliary disease, and 10 with nonbiliary liver disease.

SEQUENCE/FIELD STRENGTH

MRCP data were acquired using heavily T2 -weighted 3D multishot fast/turbo spin echo acquisitions at 1.5T and 3T.

ASSESSMENT

Digital instances of the phantoms were synthesized with varying resolution and signal-to-noise ratio. Physical 3D-printed phantoms were scanned across six scanners (two field strengths for each of three manufacturers). Human subjects were imaged on four scanners (two fieldstrengths for each of two manufacturers).

STATISTICAL TESTS

Bland-Altman analysis and repeatability coefficient (RC).

RESULTS

Accuracy of the diameter measurement approximated the scanning resolution, with 95% limits of agreement (LoA) from -1.1 to 1.0 mm. Excellent phantom repeatability was observed, with LoA from -0.4 to 0.4 mm. Good reproducibility was observed across the six scanners for both phantoms, with a range of LoA from -1.1 to 0.5 mm. Inter- and intraobserver agreement was high. Quantitative MRCP detected strictures and dilatations in the phantom with 76.6% and 85.9% sensitivity and 100% specificity in both. Patients and healthy volunteers exhibited significant differences in metrics including common bile duct (CBD) maximum diameter (7.6 mm vs. 5.2 mm P = 0.002), and overall biliary tree volume 12.36 mL vs. 4.61 mL, P = 0.0026).

DATA CONCLUSION

The results indicate that quantitative MRCP provides accurate, repeatable, and reproducible measurements capable of objectively assessing cholangiopathic change. Evidence Level: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:807-820.

Sonographic measurement of normal common bile duct diameter and associated factors at the University of Gondar comprehensive specialized hospital and selected private imaging center in Gondar town, North West Ethiopia

Background

The biliary tree is a three-dimensional system of channels that bile flows from the hepatocytes to the gallbladder and to the intestine. Size of the common bile duct (CBD) is a predictor of biliary obstruction and, therefore, its measurement is an important component of biliary system evaluation. Factors like age, height, weight, BMI, previous cholecystectomy, drugs, and type of imaging modality affect CBD diameter, but the duct significantly dilated due to obstructive biliary pathology.

Objective

To measure the normal CBD diameter and its association with age, sex, and anthropometric measurement at the University of Gondar Comprehensive Specialized Hospital and selected private imaging center, Gondar town, Northwest Ethiopia, 2019.

Methods and materials

Institutional based cross-sectional study was conducted on 206 subjects without any history of hepatobiliary abnormality. The CBD measured at the proximal part just caudal to the porta hepatis. Descriptive analysis, student t-test, one way ANOVA, correlation and both bivariable and multivariable linear regression analysis were implemented. In bivariable linear regression variables with p-value, less than 0.2 were selected for multivariable analysis and in multivariable linear regression analysis variables with P-Value less than 0.05 were considered as statistically significant.

Results

The mean age of the study participants was 39.4 (range 18–87). The mean diameter of the CBD was 3.64mm 95%CI (3.52, 3.77), which ranges from 1.8 to 5.9 mm, with 65% of the participant having CBD diameter less than 4mm. The diameter of CBD significantly associated with age with a linear trend. The mean diameter in a rural area was greater than subjects living in an urban area. Independent t-test showed no statistically significant difference in CBD diameter between male and female subjects.

Conclusion

The lower limit of the CBD diameter for this study was similar to most of the studies, but the upper limit was found to be slightly lower. The diameter was significantly associated with age along the linear trend and it was progressively increased from the lower age group onwards. The diameter of CBD did not show statistically significant association with any of the anthropometric measurement.

3D Printable Vascular Networks Generated by Accelerated Constrained Constructive Optimization for Tissue Engineering

One of the greatest challenges in fabricating artificial tissues and organs is the incorporation of vascular networks to support the biological requirements of the embedded cells, encouraging tissue formation and maturation. With the advent of 3D printing technology, significant progress has been made with respect to generating vascularized artificial tissues. Current algorithms to generate arterial/venous trees are computationally expensive and offer limited freedom to optimize the resulting structures. Furthermore, there is no method for algorithmic generation of vascular networks that can recapitulate the complexity of the native vasculature for more than two trees, and export directly to a 3D printing format. Here, we report such a method, using an accelerated constructive constrained optimization approach, by decomposing the process into construction, optimization, and collision resolution stages. The new approach reduces computation time to minutes at problem sizes where previous implementations have reported days. With the optimality criterion of maximizing the volume of useful tissue which could be grown around such a network, an approach of alternating stages of construction and batch optimization of all node positions is introduced and shown to yield consistently more optimal networks. The approach does not place a limit on the number of interpenetrating networks that can be constructed in a given space; indeed we demonstrate a biomimetic, liver-like tissue model. Methods to account for the limitations of 3D printing are provided, notably the minimum feature size and infill at sharp angles, through padding and angle reduction, respectively.

Comparison of acute cholangitis with or without common bile duct dilatation

To improve the management of patients with acute cholangitis, the present study compared laboratory test variables between acute cholangitis patients with or without common bile duct (CBD) dilatation [CBDdil(+) and CBDdil(-), respectively]. The medical records of patients diagnosed with acute cholangitis and subjected to endoscopic retrograde cholangiopancreatography between February 2008 and May 2015 were retrospectively analyzed. The present study consisted of 40 men (aged 69.4±8.8 years) and 37 women (aged 68.8±11.6 years). It was observed that CBDdil(-) patients were slightly younger than CBDdil(+) patients (P=0.0976), and levels of C-reactive protein (CRP) were significantly higher in CBDdil(-) patients than in CBDdil(+) patients (P=0.0392). In addition, logistic regression analysis indicated that CRP levels were associated with the presence of CBD dilatation (P=0.0392). These data indicate that patients with acute cholangitis without CBD dilatation tend to be younger and have higher levels of CRP. Thus, in acute cholangitis patients without CBD dilatation, diagnosis should be determined using clinical symptoms and laboratory data.